Abstract

We study image enhancement of transmitted optical fields though plasmon film lenses with smooth surfaces, random rough surfaces, and sinusoidal rough surfaces. We show that the silver film lens with subwavelength roughness provides image enhancement by reducing the spatial width of the image while preserving the image integrity. Images of multiple sources at random positions are enhanced, are spatial translational invariant for subwavelength spacing, and the quality of the enhanced images is preserved. Two numerical methods, namely, the method of moments and the T-matrix method, are used to calculate the theoretical results providing a validity check of the accuracy of the solutions. The analytic small perturbation method to arbitrary orders is utilized to demonstrate image enhancement effects in the spectral domain. The role of surface plasmon polaritons (SPPs) in plasmon imaging is explained and it is shown that the surface with subwavelength roughness enhances images by suppression of the SPPs.

J. Q. Bagley and L. Tsang, “Image enhancement using rough surface effects in plasmon materials,” to be presented at the IEEE International Symposium on Antennas and Propagation, Spokane, Wash., USA, 3–8 July 2011.

Bagley, J. Q.

J. Q. Bagley and L. Tsang, “Image enhancement using rough surface effects in plasmon materials,” to be presented at the IEEE International Symposium on Antennas and Propagation, Spokane, Wash., USA, 3–8 July 2011.

J. Q. Bagley and L. Tsang, “Image enhancement using rough surface effects in plasmon materials,” to be presented at the IEEE International Symposium on Antennas and Propagation, Spokane, Wash., USA, 3–8 July 2011.

Other (3)

J. Q. Bagley and L. Tsang, “Image enhancement using rough surface effects in plasmon materials,” to be presented at the IEEE International Symposium on Antennas and Propagation, Spokane, Wash., USA, 3–8 July 2011.

Figures (11)

(a) Spatial image field for the smooth surface lens (λ0=351nm, d=0.1λ0) showing agreement of the MoM (black crosses) and the T-matrix method (red circles) with SIP numerical integration (green solid curve), and compared to the field at the same distance (Δz=0.3λ0) due to a line source in free space. (b) Corresponding image field spectra for the smooth surface lens and the line source in free space.

Spatial image field of two identical sources (spaced Δx=0.6216λ0 apart) for a periodic surface with (a) moderate height and period (h=0.03λ0/√2, P=0.33λ0) and (b) small height and period (h=0.01λ0/√2, P=0.1λ0); (c) the sources are shifted by Δx=−0.1589λ0 and (d) the amplitude of source on the right is doubled.